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Women were allowed to watch some football games in stadiums last month

Women who do not wear the abaya in places where they may be seen by men who are not related to them face being chastised by the religious police.

In 2016, a Saudi woman was detained for removing her abaya on a main street in the capital of Riyadh, Reuters news agency reported.

However in recent years Saudi women have begun wearing more colourful abayas that contrast with the traditional black, and open abayas worn over long skirts or jeans are also becoming more common in some parts of the country, Reuters says.

What is the background?

Sheikh Mutlaq's intervention follows earlier moves to modernise Saudi society, part of a social reform plan spearheaded by Saudi Arabia's Crown Prince Mohammed bin Salman, who has pledged to transform the country with the government's Vision 2030 programme.

It is aimed at giving more freedom to Saudi women, who face strict gender segregation rules, and follows the historic lifting of a driving ban in September 2017.

In the same month, women were allowed to participate in Saudi Arabia's National Day celebrations for the first time.

Last month women were permitted to watch football live in stadiums in some cities.